Written by Thomas Godwin
Updated: May 1, 2023
Image Credit ©


An organism covers a wide variety of life, including the capability for reproduction, growth, adaptation, reaction to outside forces, and homeostasis. Animals of every type and every living thing in the phylogenetic tree fall under this umbrella.

Types of Organisms

There are nine types: producers, consumers, herbivores, carnivores, scavengers, omnivores, parasites, predators, and decomposers. Those nine terms cover every living thing on the planet, above the water and below.

Organisms in the Kingdoms of Living Things

Categories exist to place organisms in certain classes. In this case, the five kingdoms of living things include Fungi, Plants, Monera, Protista, and Animals. There are some lists with only three living things and some with seven but five is the broadest and most widely accepted.


Organisms in the fungi kingdom include mushrooms, toadstools, mold, mildew, and anything with chitin in its cell walls. These organisms typically reproduce by spreading spores in a variety of ways but mostly through human and animal disruption.

photo under microscope of fungi growth on the plant cells
Fungi is one of the five kingdoms of living organisms.



Eukaryotic and multicellular, the plant kingdom is the oldest of the five. It includes hundreds of thousands of types of vegetation, including trees, flowers, grasses, and more. Thanks to the process of photosynthesis, plants take in carbon dioxide and release oxygen.


The animal kingdom includes two groups of organisms – vertebrates, and invertebrates. It may sound sort of obvious but animals stand separate from the other kingdoms because they can move. Animals are also the most diverse of all the kingdoms.


Protista is the most difficult for scientists because they have trouble categorizing it. However, it’s mostly a category for everything that doesn’t fall under the other four kingdoms.

Dunaliella, flagellated green alga (Chlorophyceae, Protista), microscope image of large number of living cells shwoing flagella, cell walls, chloroplasts and eyespots (stigma)
Protista is largely considered a catch-all category for organisms that don’t fit within the other four kingdoms.

©Maple Ferryman/


Monera is the microscopic kingdom, including all things we cannot see, such as bacteria, viruses, and archaea. Everything in the monera kingdom is a single-cell organism and none of these organisms have a defined nucleus.

Most Common Organism in the World

Insects are the most common species of organism on the planet, with well over a million known species still in existence throughout the world. At a “number of individuals” level, insects also own the crown. Some scientists estimate as many as 30 million species, with individual insect organisms numbering well into the billions.

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About the Author

Thomas is a freelance writer with an affinity for the great outdoors and Doberman Pinschers. When he's not sitting behind the computer, pounding out stories on black bears and reindeer, he's spending time with his family, two Dobermans (Ares and Athena), and a Ragdoll cat named Heimdal. He also tends his Appleyard Ducks and a variety of overly curious and occasionally vexatious chickens.